"With this use we have noticed that there seems to be a total lack of care of the place," Theresa says.
"There is so much rubbish being left behind that is making us very angry and extremely sad."
That rubbish includes used nappies and wet wipes, alcohol cans and bottles that fill their recycling bin when they tidy up.
"Te Pahu is a wonderful rural place to live with an eclectic and interesting and caring community, but we are sick of people spoiling it with rubbish," Theresa says.
They want to see more awareness by visitors and believe that is up to DoC and Waipā District Council.
The couple wrote to both organisations on February 16 outlining their concerns.
They even suggested solutions, such as more signage, more bins, visits from rangers or staff and more enforcement.
To date DoC has not replied and council acknowledged receipt of the mail and gave the event a reference number.
As well as the rubbish concerns, the couple worry about people ignoring the no dog rule.
They say whenever they are there they see about three dogs being exercised.
On the day they wrote their complaint, they collected a sack of rubbish and saw three dogs off leads.
They worry about the effects on birdlife being re-introduced to the mountain if dogs are wandering unrestrained.
There is also evidence that people are camping overnight, also forbidden, and open fires are being lit.
Plus many of the signs that are in the reserve are covered in graffiti.
"The blatant lack of respect for the rules is getting worse this summer compared to previous years," Theresa says.
She says if they attempt to inform offenders of the rules it falls on deaf ears and they are concerned this beautiful part of New Zealand will be ruined for future generations.
The couple will do what they can to keep Kaniwhaniwha Reserve as pristine as possible, and hope the authorities in charge will do their bit as well.